Regulatory control of the German radioactive waste management system

In Germany, all radioactive materials are controlled from their origin to their final disposal or release. This is in accordance with the IAEA draft Convention on the Safety of Radioactive Waste Management. A Waste Control System has been developed and is now available. Although the IAEA and EU regulations allow disposal outside the country of origin this philosophy is not in compliance with the present German disposal concept. As a consequence, Germany will not grant licences for the import of radioactive waste for final disposal or for export for disposal in a foreign country. Thus, unconditional clearance is a prerequisite if the final destination is outside Germany. However, Germany will closely follow all international developments in the field of radioactive waste disposal.     

Hyperoxia increases paradoxical sleep rhythm in the pontine cat

Pontine cat is an ectothermic preparation, whose central temperature can artificially be lowered from 36 degrees C to 26 degrees C; this gradual hypothermia is accompanied by a dramatic increase in paradoxical sleep (PS). Two main hypotheses might explain this result: executive systems of PS might be switched on gradually by cold-sensitive thermodetectors, whereas inhibitory monoaminergic mechanisms appear to be warm-sensitive. On the other hand, energy saving mechanisms peculiar to hypothermia might promote PS appearance. Indeed, in normal animals, PS is selectively suppressed both by hyperthermia and hypoxia. The inhibitory effect of hypoxia might explain why hypothermia, which protects the brain against hypoxic alterations, might facilitate PS. If this last hypothesis is correct, the putative increase in cerebral oxygen supply might increase PS. For this reason, we submitted eight pontine carotid-deafferented cats, kept at the same central temperature (34 +/- 0.5 degrees C: temperature clamp) to periodic hyperoxia (PaO2 = 58 +/- 7 kPa) or room air (PaO2 = 17 +/- 2 kPa) alternatively during 4- or 12-h periods. Hyperoxia induced an 85% increase in PS, mainly due to an increase in PS rhythm (PS cycle duration was 65 +/- 4 min in normoxia and 45 +/- 4 min in hyperoxia, p<0.0001). In five animals, after hyperoxia, PS cycle returned gradually back to control values in 4 to 12 h. These findings show that PS is exquisitely sensitive to conditions that impair oxidative metabolism. The role of cholinergic executive PS systems as putative metabolic-sensitive neurons remains to be established.     

Treatment of Stress Urinary Incontinence with Muscle Stem Cells and Stem Cell Components: Chances,Challenges and Future Prospects

Urinary incontinence (UI) is a major problem in health care and more than 400 million people worldwide suffer from involuntary loss of urine. With an increase in the aging population, UI is likely to become even more prominent over the next decades and the economic burden is substantial. Among the different subtypes of UI, stress urinary incontinence (SUI) is the most prevalent and focus of this review. The main underlying causes for SUI are pregnancy and childbirth, accidents with direct trauma to the pelvis or medical treatments that affect the pelvic floor, such as surgery or irradiation. Conservative approaches for the treatment of SUI are pelvic physiotherapy, behavioral and lifestyle changes, and the use of pessaries. Current surgical treatment options include slings, colposuspensions, bulking agents and artificial urinary sphincters. These treatments have limitations with effectiveness and bear the risk of long-term side effects. Furthermore, surgical options do not treat the underlying pathophysiological causes of SUI. Thus, there is an urgent need for alternative treatments, which are effective, minimally invasive and have only a limited risk for adverse effects. Regenerative medicine is an emerging field, focusing on the repair, replacement or regeneration of human tissues and organs using precursor cells and their components. This article critically reviews recent advances in the therapeutic strategies for the management of SUI and outlines future possibilities and challenges.     

Activity–Composition Relations in NiAl2O4─MnAl2O4 Solid Solutions and Stabilities of NiAl2O4 and MnAl2O4 at 1300° and 1400°C

Activities of NiO were measured in the oxide and spinel solutions of the system MnO–NiO–Al₂O₃ at 1300° and 1400° C with the aim of deriving information on the thermodynamic properties of the spinel phases. Synthetic samples in selected phase assemblages of the system were equilibrated with metallic nickel and a gas phase of known oxygen partial pressures at a total pressure of 1 atm. The data on NiO activities and directions of conjugation lines between coexisting oxide and spinel phases were used to establish the activity–composition relations in spinel solid solutions at 1300° and 1400°C. The MnAl₂O₄–NiAl₂O₄ solid solutions exhibit considerable negative deviations from ideality at these temperatures. The free energy of formation of MnAl₂O₄ from its oxide components (MnO + Al₂O₃) at 1300° and 1400°C is calculated to be −24.97 and −26.56 kJ. mol⁻¹, respectively. The activities determined in the stoichiometric spinel solid solutions are more negative as compared with those predicted from cation distribution models.     

Activity–Composition Relations of Chromium Oxide in Silicate Melts at 1500°C under Strongly Reducing Conditions

The solubility and activity–composition relations of chromium oxide in melts of the systems CaO–CrO _x –SiO₂ and CaO–Al₂O₃–CrO _x –SiO₂ have been determined at 1500°C by equilibrating melts with Pt–Cr alloys at known oxygen pressures. It is shown that the increase in the concentration of divalent chromium ions, as the oxygen pressure and the basicity of melt decrease, results in a dramatic increase in the solubility of chromium oxide in the liquid phase. An increase in the Al₂O₃ content of the melt leads to a decrease in the solubility of chromium oxide over the whole composition range studied. The activity coefficient of CrO has been found to increase with increasing melt basicity and decreasing oxygen pressure whereas the activity coefficient of CrO_1.5 decreases sharply with increasing melt basicity for siliceous melts but levels off at a basicity ratio (wt% CaO/wt% SiO₂) of about 0.7. An increase in the Al₂O₃ content of the melts results in an increase in the activity coefficient of CrO.     

Detection of colorectal adenoma and cancer based on transthyretin and C3a-desArg serum levels

Colorectal cancer is the second leading cause of cancer death, and it develops from benign colorectal adenomas in over 95% of patients. Early detection of these cancer precursors by screening tests and their removal can potentially eradicate more than 95% of colorectal cancers before they develop. To discover sensitive and specific biomarkers for improvement of pre‐clinical diagnosis of colorectal adenoma and cancer, we analysed in two independent studies (n = 87 and n = 83 patients) serum samples from colorectal cancer (stage III), colorectal adenoma and control patients using SELDI‐TOF‐MS. Extensive statistical analysis was performed to establish homogeneous patient groups based on their clinical data. Two biomarkers that were each able to distinguish control patients from either colorectal adenoma or colorectal cancer patients (p<0.001) were identified as transthyretin (pre‐albumin) and C3a‐desArg by MS/MS and were further validated by antibody‐based assays (radial immunodiffusion, ELISA). A combination of both proteins clearly indicated the presence of colorectal adenoma or carcinoma. Using a cut‐off of <0.225 g/L for transthyretin and >1974 ng/mL for C3a‐desArg, we found a sensitivity and specificity for colorectal adenoma of 96% and 70%, respectively.     

Heat exchange between strands and guide rollers in the secondary cooling zone of a slab continuous casting machine

Measuring of temperatures at different distances from the surface of the guide rollers without inside cooling in the secondary cooling zone of slab caster. Computation of the temperature field of the rollers and the flows of heat into and out of the rollers by using mathematical models. Discussion about the influence of the length of the strand and the cooling conditions. Comparison with the heat transfer by spray cooling.     

Vermischungsvorgänge beim Stranggießen

Die Untersuchung stationärer und instationärer Zustände beim Sequenzgießen auf einer Brammenstranggießanlage hat Informationen über die wichtigsten Einflußparameter auf den Ablauf der Vermischungsvorgänge geliefert. Je nach betrieblichen Gegebenheiten und Erfordernissen können Gießstrategien zur Abflachung oder Aufrichtung der vermischungsbedingten Konzentrationsverläufe im festen Strang angewendet werden. Die modellmäßige Beschreibung der Mischvorgänge wurde unter vereinfachenden Annahmen und erster Näherung nach dem Konzept der Kaskade mit seriellen Mischzellen vorgenommen. Es ist zu erwarten, daß die Mischvorgänge beim Stranggießen in Zukunft wegen steigender Ansprüche an die Gleichmäßigkeit des Produktes im Mittelpunkt von Entwicklungsarbeiten stehen werden.